guest ::
| Home > Publications database > Hydration and dehydration at the tropical tropopause |
| Home > Publications database > Hydration and dehydration at the tropical tropopause |
| Book/Habil / Postdoctoral Thesis (Non-german Habil) | FZJ-2015-07777 |
2015
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag
Jülich
ISBN: 978-3-95806-101-9
Please use a persistent id in citations: http://hdl.handle.net/2128/9621
Abstract: Changes of stratospheric water budget are connected to the water entry which is set by the cold trap at the tropical tropopause. Airborne measurement of water over the Indian Ocean, Brazil, Australia and Burkina Faso are used to investigate, along which pathways air is freeze-dried on its way into the stratosphere and which conditions control the freeze-drying processes. The results critically depend on the accuracy of the data set which is compared to that of other scientists in field and laboratory experiments. The tropical water entry is a highly complex interplay between freeze-drying in the coldest regions of the tropical tropopause layer and fresh supply of water by convection or by mixing with tropospheric air. Trajectorybased reconstruction of water yields a remarkable agreement with the observations and proofs the concept that stratospheric water entry is primarily controlled by the coldest regions in the tropics. The net effect of deep convection is moistening, locally also above the tropopause. However, no indication of a global convective impact on the stratospheric water budget can be derived. Thus large-scale transport is dominant compared to that by convection. Cirrus clouds are a key parameter in the freeze-drying process, and their ice water content is an indication on their hydration or dehydration potential. The cloud formation critically depends on the relative humidity. In contrast to some recent studies, the data set here confirms the atmospheric distribution of saturation in agreement with accepted theories. The observed moderate supersaturations have only a limited impact on the water entry.
|
The record appears in these collections: |
PDF
PDF (PDFA)